1. Field of the Invention
The present invention relates to a SCUBA (self-contained underwater breathing apparatus) air tank strap tightening actuator, and more particularly, to a tightening actuator for securing a SCUBA diver's air tank to his or her backpack or buoyancy compensator (BC) by means of a strap which engages the backpack or BC and surrounds the tank with the two free ends of the strap being hooked to said actuator around said tank.
2. Description of the Prior Art
SCUBA tank securing straps for attaching the air tank to a diver's backpack have in the past used tank strap locking clamps such as were used for early automotive and aircraft seat belts. The free end of the belt is fitted through a clamp which, when it is closed, rotates a spiral ramp to narrow the gap in the belt track of the clamp to engage the belt between the ramp and the flat in the track. The ramp has a roughened surface which bites into the belt to prevent it from pulling out of the clamp. In order to release the belt, it must be pulled slightly tighter to allow the ramp to rotate out of engagement with the belt whereby the belt can then be pulled out of the clamp.
These belt tightening clamps, although they have been used for many years by SCUBA divers, are unsatisfactory for the reason that they cannot be fully tightened and they stretch to some degree when they get wet. A seat belt type of clamp cannot be fully tightened because the final clamping requires a pull on the belt in the loosening direction to set the clamp. This action loosens the belt slightly from its tightest position, and this slight loosening is very detrimental in this application because the strap is so short that the least loosening of it is a very significant percentage of elongation, and such a strap also requires considerable force to tighten it because it has very little stretch when it is dry.
This type of strap cannot be tightened after the diver goes underwater, where it stretches when it gets wet, because of its operative location high on the diver's back. There has long been a need for a new way to tighten these straps. Pre-wetting the strap to take out the stretch has not proved to be a solution since it takes too long to do, and it usually means disassembling the backpack to get the strap free whereby it can be conveniently submerged to get it wet. Therefore, a means has long been needed to put considerable force in the strap to remove any stretch and thereby tighten the strap securely around the tank and to secure the tank to the backpack of the SCUBA diver before he enters the water where the strap might stretch slightly and which will automatically take any stretch out of the strap if it occurs.